Think, Darko, think!
The SR is a fixed focus camera with a 30 mm lens. The lens is on a fairly narrow tube. The camera's back comes off for loading film, so you could in principle set up a different lens to be in focus at some distance or other. You could even bodge a helical for another lens on the front of an SR and bodge it to focus the lens it is made for at infinity.
No cheap or easy. And short lenses in shutter that cover 76 mm are very expensive. I don't have an SR, so I can't be sure but I expect that a lens much longer than 30 mm will vignette on 72x24 unless you do major surgery on the front of the SR. You would be better off shooting a 6x7 camera and cropping to 68 x 24.
Or, if you don't want to pay the XPan price, get a humble Century Graphic (make sure to get one that still has a focusing panel) and a roll holder to fit. Depending on the roll holder you select, it will shoot 56 x (78 to 82) on 120 film. If you want to crop to 24 mm high, you can get between 78x24 to 82x24. Sorry, no sprocket holes. Lenses that will work on a Century Graphic include 35/4.5 Apo-Grandagon, 38/4.5 Biogon (won't cover nominal 6x9, just loses the corners of 82x24 [I have one, that's how I know]), 47 mm Super Angulon, ..., up to around 250 mm telephoto lenses. Who needs an XPan?